The provided usage example is bad for accessibility: the name of the icon, e.g. ”check_circle”, will be announced by screen readers. If there is other contextual information that explains the icon, the icon can be hidden from screen readers using aria-hidden=”true”. However, in cases where the icon appears stand-alone, it needs to contain a human-understandable text that explains its meaning. Also, never use Google’s…
“Check-circle” is exactly the amount of information that the able reader has. Sight-deficient users are as much used to those weird words as able users are used to unintelligible icons.
It would be trivially easy to use ARIA attributes to indicate which span is the icon's label. Not something most people consider, but this is Google. At least they have an accessibility icon?